Despite the looming fear Sydney's housing bubble is set to burst, agents are ­continuing to invest in marketing to Chinese-Australians, erecting advertising signs in Mandarin only, and hiring buyer's agents who speak the language.

One agent advertising in the city's inner northwest" where some suburbs have a Chinese population of more than 30 per cent" has a billboard in Mandarin at the busy Rhodes train station

The sign for of LJ Hooker Rhodes agent Tim Wu, urges locals in Mandarin to consider his agency as their first choice.

A spokesman for the agency said Mr Wu advertised his buying and selling skills on Chinese and English billboards, but would not elaborate on why it was necessary to post some signs entirely in Mandarin.